Speculations

Kel is probably George & Brenda's Great grandchild while Dave's Grandchild. I think Susie and Dave got married, had a child, and he (Dave & Susie's child) got married, also had a child (Kel) then had conflict with eachother. Dave must be her grandpa.

Kel drowned herself now she cant be at peace. Its not a natural death. She cant be free like The ghosts. Maybe this is why she can't be heard by the other people? Maybe the ghosts are helping her rest in peace?

Maybe this is how they're all connected?